The present invention relates to a knee bag for restraining a movement of knees of an occupant in a vehicle in an event of a collision of the vehicle so that a lower body of the occupant does not move toward a front side of the vehicle to prevent lower legs of the occupant from striking against an interior panel in front of a seat. The present invention also relates to an occupant leg protection system including the knee bag.
An occupant leg protection system protects lower legs of an occupant from striking against an interior panel in front of a seat, so that the lower legs do not receive a large load in an event of a head-on collision of a high-speed mobile unit such as an automobile. Such an occupant leg protection system includes a knee bag to be inflated toward the front of the occupant legs and an inflator (gas generator) for inflating the knee bag.
Japanese Patent Publication (Kokai) No. 2003-182504 has described a knee bag to be inflated upwardly from below in front of occupant legs. The knee bag is formed such that a lower part thereof has a width in a lateral direction (hereinafter, also referred to as a lateral width) decreasing toward a lower end. A diffuser diffuses gas from an inflator in the lateral direction in the knee bag. Tethers are provided for joining a base fabric of the knee bag adjacent to the occupant and a base fabric adjacent to an instrument panel (interior panel), and are disposed vertically in multistage.
In Japanese Patent Publication (Kokai) No. 2003-182504, the tethers are structured such that the uppermost tether has the smallest lateral width. Accordingly, an outline of the uppermost chamber of the knee bag becomes unclear, and this may delay completion of inflation of the uppermost chamber.
In view of the problem described above, an object of the present invention is to provide a knee bag to be quickly deployed vertically and laterally, and an occupant leg protection system including the knee bag.
Further objects and advantages of the invention will be apparent from the following description of the invention.